Probability of coming into existence again ?

The problem is the mental construct of "I". Yes we can't help but believe that there is feeling, thinking, subjective experience etc. The problem is that our brain seems to naturally construct a concept of "I" which is a sort of owner of these subjective experiences that persists over time. This construct, while deeply engrained and probably useful, is not consistent with physical reality. This can be seen either with teleporter type thought experiments or to some extent with real life cases of brain trauma (for example in Oliver Sacks's or Ramachandran's books). Our brains' care about protecting some potential future entities, which barring crazy technology or anthropic scenarios are easy to specify, but there is not going to be a coherent general principle to decide when we should count potential future entities as being us.

There doesn't seem to be any reason why I should be experiencing these specific qualia instead of others, that I "popped into existence" as this specific consciousness instead of another, or that I perceive time subjectively.

..assuming that the I is separable from memories and experiences. Otherwise, you are what you are..

Based on what I know, and that qualia occur, what is the probability (if any) that I will pop into existence again and again, and experience different qualia each time, with no subjectively perceivable connection with the "previous" consciousness?

That still requires the separate I assumptions. Otherwise, it is no different from a bunch of different people experiencing different things.

does suffering have a limit or is it infinite?

If suffering is infinite, likely joy is too. Why not let the infinities cancel out?

I think the probability of you popping into existence again is (1) very small and (2) depends on how you define your "self." Would you consider an atom-for-atom copy of you to be "you"? How about an uploaded copy? etc. The simple fact is that physicists have constructed a very simple model for the universe that hasn't been wrong yet and, so, is very likely to be correct in the vast majority of situations - your existence should be one of them. Faith in the accepted model of the universe constructed by modern physicists can be justified by any reasonable prior coupled with Bayes' theorem. Thus, you can be extremely (99.999%+) that you won't pop into existence with infinite suffering (technically 0 and 1 aren't commonly accepted as probabilities on LessWrong).

Moving on, you will almost certainly not live forever (suffering or otherwise), because, quite simply, the universe will experience heat-death at some point. Justification for this belief is, similarly, based on Bayesian updating.

As a side-note. You say

Similar to what happens if there is no free will and thus nothing matters since no change is possible?

I'm not sure free will is a meaningful mental category when used in philosophy. If we lived in a deterministic universe, I, personally, would still believe that life had value. Ultimately, our universe is either deterministic or it isn't, but I fail to see why this would have any important philosophical implications. Why would it be good if our universe contained randomness?

You might consider reading "Possibility and Could-ness" if you haven't done so for an alternative perspective on what free will actually is.

I think you are making an unjustified assumption, e.g. "... that I will pop into existence again...", that there is an "I". There is a pattern of information that feels that it experiences qualia, and then later possibly there is another pattern of information that feels that it experiences qualia, and possibly with additional information representing memories corresponding to the first set of information. Shifting to this viewpoint dissolves the question. If we accept that qualia is an illusion then we still have an interesting question about how the illusion occurs, but many other tricky issues go away.

Some of the other questions that you refer have been disspelled in their related discussions. There seems to be some carry over confusion but I am gonig to focus on main question you are posing.

I can see a possible hole in that you mix what "your" possible expriences might be with the possibility that other view points existing. That is if other have qualia they are not your qualia. There are actuallky arguments about how a computers state can only be based on information that has physical access to it. Combined with relativity that means that indeed computers percieve time subjectively. You raised this as a lack of imagination/lack of suggestions issue. If you don't find these claims compelling that is a separate concern of validity.

If the question of subjective observing can be rephrased as "does computation ever end?" The answer will be prettty much no, althought "human-like" computation might come to a permanent end.

Also even at the risk of being corny "What is an ocean but a multitude of drops?". That these moments will be lost in time as "tears in the rain" doesn't mean that they are not kickass moments.

Also if the "new" conciousness doesn't have psychological connection why the need for time dependence? Why can't the new the conciousness start while the old one is running? As in why would suicide have any impact for an unrelated counciousness start? If you take your viewpoint and arguments seriously you should be worried that you migth live lifes as the other you are currently interacting with. This can be potentially be more emphatethic viewpoint as in effect you live as everyone and makes altruism a form of egoism. But this risks blurring the line between you (r current incarnation) and others.

If you don't seriously believe that you could experience later other peoples qualia and the issue is "time doesn't work like that", then you might be positing a strange feeler that "snaps" into different viewpoints. What is this entity like when it is not snapped to anything? Why is it still subject to strict chronology if it doesn't have physical parts? You are mixing up a subjective time and ontological time. Your capabability to receive qualia will not have ontological inertia after your subjective time has come to an end. There is a realted question of of "terrible lives might be possible, how do we avoid them from happening?" but I am reading that you are posing a question of "how do I avoid for it to happening to me". A terrible life will happen obvoiusly happen to the person that borns intot hat unfornate position, but for most resonable defintions it can't be you.

How would you distinguish you popping into existence with different qualia (and different memories/personality/etc.) from someone else popping into existence with different qualia (+memories/personality/etc.)? As others have argued, I think the flaw in the reasoning is that there is a privileged "I" that you are that is separate from the body/mind you wear.

If you permit a reincarnation after a long time - and I really don't see why one shouldn't - what would prevent a synchronous reincarnation then?

I guess, nothing as well.

The first part of your question has been addressed in this paper, which can be summarized like this.

Existence may be pointless. But isn't it better than having never existed at all?

I've often wondered how the Universe even exists. It seems to me eternal Nothingness, no consciousness, no matter, no forces, no computation, no existence of any kind is far more probable.

The best way of looking at it I've found is to ask this question: Is an imaginary pink dragon real to itself?

Regarding the embodiment of you ever occuring again, I'm pretty certain our universe is finite and eternal, has existed forever in the past and will exist forever into the future. Like an endlessly shuffled deck of cards, it is a statistical certainty that all possible arrangements of the deck (52 factorial) will be visited an infinite number of times. All possible arrangements of the matter in our universe have been visited already an infinite number of times...

The universe didn't have to have a beginning, any more than the sin(t) function does. It's defined for all t.